1. Field of the Invention
The present invention is directed to insulation and insulation arts. In particular, this invention is directed to insulation which is adapted for use underneath slabs of construction material such as concrete.
2. Description of Related Art
In the construction and building industries, various types of insulation have been used to minimize heat transfer. For instance, it has been known to insulate concrete driveways, walkways, and foundations by placing a sheet of insulating material between the ground and slab of concrete. In addition, it has also been known to utilize insulating material in the construction of building freezers, coolers, and food processing facilities where the temperature control is significant. In such applications, insulating materials are provided within the walls of the facility to again, minimize heat transfer.
Various multi-layered insulating materials are known in the art. For example, U.S. Pat. No. 5,100,725 to Pearson discloses an insulation and heat reflective barrier that includes a plurality of radiant heat barrier layers at the core, and a pair of foam insulating material which is adhered to the radiant heat barrier layers via an adhesive. In addition, U.S. Pat. No. 5,316,835 to Groft et al. similarly discloses a low emissivity insulation wherein a polyethylene foam core is provided with an aluminum layer on each side.
Despite the known art, an effective insulation product which can economically be used to insulate slabs is not known in the art. In particular, an economical insulation which provides adequate resistance against conductive heat transfer to/from construction slabs is not readily available in the marketplace. The available insulation for slabs using construction also do not provide resistance to radiative heat transfer and may also allow moisture and caustic materials from the slab to seep through the insulation.
In view of the above, there exists an unfulfilled need for an insulation which can effectively be used to insulate slabs used in construction such as slabs of concrete, as economical, and avoids the limitations of the presently available insulation products.
In view of the foregoing, one advantage of the present invention is that it provides multi-layer slab insulation that may be used to insulating slabs used in construction.
Another advantage of the present invention is that it provides a multi-layer slab insulation that minimizes radiative heat transfer through the slabs.
Still another advantage of the present invention is that it provides a multi-layer slab insulation having extending lips that facilitate installation and increases effectiveness of the insulation.
These and other advantages are attained by a multi-layer slab insulation in accordance with one embodiment of the present invention having an aluminum layer, a first foam layer positioned on one side of the aluminum layer, and a second foam layer positioned on another side of the aluminum layer. In one embodiment, the first and second foam layers are polyolefin foam layers such as polyethylene foam and polypropylene foam having a thickness of 0.25 to 0.5 inch.
In accordance with one embodiment, the aluminum layer of the multi-layer slab insulation includes an aluminum foil having a thickness of 0.00025 to 0.0005 inch. In this regard, the aluminum layer may be made of 1100-1145 wettable aluminum. In addition, a first strengthening layer may be positioned between the aluminum foil and the first foam layer, and a second strengthening layer may be positioned between the aluminum foil and the second foam layer. The strengthening layers may be extruded lineal low density polyethylene films having a thickness of approximately 0.001 inch. Preferably, the first and second foam layers, first and second strengthening layers, and the aluminum layer are laminated together by applying heat or by applying an adhesive.
In accordance with another embodiment, the aluminum layer of the multi-layer slab insulation includes a metallized film. In another embodiment, the metallized film is a polyolefin film or a polyester film with aluminum coating thereon. Preferably, the first and second foam layers, and the metallized film are laminated together.
In accordance with another aspect of the present invention, a multi-layer slab insulation is provided with a first polyolefin foam layer that is offset relative to the second polyolefin foam layer to provide a first extending lip on the first polyolefin foam layer and a second extending lip on the second polyolefin foam layer. In another embodiment, the second polyolefin foam layer is larger in width than the first polyolefin foam layer to provide two extending lips on the second foam layer. Moreover, at least one extending lip may be provided with an adhesive to adhere to an extending lip of an adjacent multi-layer slab insulation.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention when viewed in conjunction with the accompanying drawings.